The purpose of this investigation is to allow a collaborative study on the presence of skeletal muscle hydrophobic proteoglycan structure and function between Dr. David Carey's laboratory, (Geisinger Clinic, Weis Center for Research, Danville, PA) and Dr. Enrique Brandan's laboratory (Faculty of Biological Sciences, Catholic University of Chile, Santiago, Chile). The long term goals of this proposal are to understand the biological functions of skeletal muscle plasma membrane proteoglycans. The specific aims of this proposal are to identify and characterize transmembrane and phosphatidylinositol-linked proteoglycans and to study the time course of the expression of the hydrophobic proteoglycans during muscle differentiation. These studies will complement ongoing research in Dr. Carey's laboratory dealing with the biochemistry, neurobiology and molecular biology of hydrophobic proteoglycans, and the cell biology and physiology of sulfated macromolecules in Dr. Brandan's laboratory.